Paper manufacture



Patented- A r. 12, 1927.

- UNITED I STATES! 1,624,492 PATENT OFFICE.)

ARTHUR D. LITTLE, F BROOKLINE, AND CARROLL E. CARPENTER, OF MELROSE,MAS- SACHUSETTS, ASSIGNORS TO ARTHUR D. LITTLE, IN 0., OF BOSTON,MASSACHUSETTS,

A CORPORATION OF MASSACHUSETTS.

' PAPER MANUFACTURE.

No Drawing.

Our present invention relates to the art of making paper from wood pulp,and particularly to the manufacture of newsprint papeiz, Its objectis tomake available for the uses of that manufacture, and for analogous.uses, certain woods, particularly the southern pines of various speciesand southern hard woods of the class known as gumwood, which haveheretofore been found ununworkable wood fiber mixture or furnishcomposedof the aforesaid ingredients into a furnish that is workable on thepaper machine, by the incorporation in the unworkable furnishofaflocculent agglutinant, preferably colloidal cellulose, conveniently,but not necessarily, produced by hydrating a part of one of theingredients of the unwork- 8 able furnish. Our invention also embraces.

the method or steps .involved in so transforming sucha furnish,-and theresulting products, including the finished product, newsprint paper madefrom southern pine and gumwood; as will more fully appear from thefollowing detailed description.

Preliminary to a description of the invenp tion, a brief discussion ofthe qualities required in newsprint paper, and of the characteristics,.with reference to the making of paper, of the woods above named andthose heretofore used for making newsprint paper, will be helpful.Newsprint paper must have strength enoughpto carry it 'through theprintingvpress at high speed, proper body and hardness, and anabsorptive quality suf- -ficient to absorb quickly the liquid vehicle ofthe newspaper printing inks. Itmust also be light'in color, as nearlywhite as practicable. These conditions'have been'met heretofore bymaking such paper of a mixture of chemical wood pulp, the relativelylong fibers of which give the required tensile strength, and ground woodpulp to give the Application filedMarch' 30, 1925. Serial No. 19,283.

required body and absorptive qualities and reduce the ,cost. commercialoutput of such paper is now, and long has been, made from the woods ofthe northern conifers, namely, spruce, fir, hemlock, larch, etc.;chemical pulp being made from these woods by the sulphite process. Theground wood pulp always predominates largely over the chemical pulp, anda very common proportion is seventy-five percent of the "former totwenty-five percent of the latter.

The southern pine woods have fibers much longer than thosev of thenorthern conifers,

but they also have a high content of resin,

many times that of the northern conifers. On account of this high resincontent, the southern pines cannot be advantageously made into pulp bythe s'ulphite process or by grinding. A long fibered stock may bereadily prepared from thesouthern pines by the sulphate process, but thepulp so made;

Substantially the entire have relatively short fibers and a low resincontent, wherefore they are well adapted to be made into pulp bygrinding and the mechanical pulp so made from gumwood has the color andabsorptive qualities required of the ground wood component of newsprintpaper.

But when mechanical pulp is produced from gumwood by methods of grindingat resent ordinarily practiced, the separate particles of the wood thusobtained are so short in average length, and have such inferior feltingqualities, that such pulp cannot be handled by the paper machine andmade into satisfactory newsprint paper either alone or in admixture withpermissible proportions of long fibered chemical pulp.

For the reasons above indicated no newsprint paper is now made in theSouth or from southern woods, notwithstanding that the consumption ofsuch paper inthe Southern. States is in the neighborhood of fifteenhundred tons per day, and that vast quantities bf gumwoods and southernpines are found in the Southern States in convenient access to themarkets in those States; and in spite of the fact, also, that the pricesof The proportion o these woods ha ve for many years been much lowerthan the prices of pulp wood in the North.

The primary problem involved in attaining our object of making availableto the paper industry, for the purposes above stated, the great suppliesof southern pines and gumwoods, was to find a means by which gumwoodground pulp, in admixture with permissible proportions of long 'fiberedchemical pulp, could be made into a workable paper furnish. In thesearch for a solution of this problem we have carried out a long andcostly series of experiments, 1n the course of which we have attemptedto obtain, by grinding gumwood with a wood pulp grinder of the type nowcommercially used, mechanical pulp which, in admixture with permissibleproportions of long-fibered chemical pulp would pass over the papermachine. Although we made many such attempts, with various adjustmentsof the wood pulp grinder and with various modlfications in the dressingof the stones, the

fibers of the wood were so generally broken into short lengths by thegrinder, that we were not able to obtain from gumwood by such means,mechanical pulp of the felting qualities and other characteristicsrequired of the ground wood component of newsprint paper.

We succeeded, and were the first to succeed, in bleaching southern pinesulphate pulp, by careful control of the bleaching process, to a colorwhich permits of its use (in white paper, with conservation at the sametime of the necessary strength of the fibers, thus solving the secondaryproblem of making this pulp usable as the longfibered feltablecomponent. of such paper. But paper made entirely of such bleachedsulphate fiber or with a major component thereof in admixture withgumwood ground pul is not suitable for newsprint paper, while fibermixtures containing permissible pro ortions of such sulphate pulp andthe qua ity of gumwood pulp which we were able to obtain by grinding,are unworkable.

The primary problem was solved by our discovery that the addition of a.small proportional content of a suitable fiocculent agglutinant to thefurnish or pulp mixture of sulphate fiber and mechanical gumwood pulp,so changed the working properties of the furnish that a web of goodformation was readily securedwhich would run well over the papermachine, presented no unusual difiiculties in manufacture and madefinished paper possessing the requisite strength and printing qualitiesfor use on high speed news aper printing presses. agglutinant which wehave found suitable is from five to ten erent by weight of the dry fibercontained in the total furnish; although a somewhat larger or smallerproportion may be used within the protection of our claims.

The agglutinant material causes the otherwise unfeltable fibers to matand interlock into a firm web, and to adhere together. It also retardsthe draining away of water from the pulp on the wire of the papermachine, so that more time is given for the fibers to thus interlock andfelt together, before the water is drawn out by the suction boxes at thedelivery end of the wire.

The water which is pulled out by the suction boxes carries with it partof the agglutinant, to wit, all that does not remain adhering to and inmesh with the fibers lying on the wire. This water is used, in part atleast, over and over again, being continuously returned to the stuffchest of the paper machine, and there added to the stock which isdelivered from the beater.

.Hence the water is a carrier or vehicle for the agglutinant, andcontinually supplies the agglutinant to the paper stock in the machine.Whatever the exact action of the agglutinant may be, its effect is atreatment of the gumwood to make the fibers thereof feltable with oneanother and with the long fibers of the pine pulp, into a firm andstrong web. It transforms an otherwise unworkable pulp mixture into afurnish which can be satisfactorily handled by a paper machine and madethereby into suitable newsprint paper. After extraction of the water,enough of the agglutinant remains in the web to serve as a binderadhering to the fibers and cementing them together, thus makingthefinished paper hard and strong enough to meet the requirements ofcommercial newsprint paper. The agglutinant preferably used is colloidalcellulose made by. beatin chemical wood pulp, or otherwise abra ing itin water, until it is hydrated to the colloidal state. Cellulose soprepared is flocculent in condition, and is pure cellulose, free fromany compounds or ingredients liable to produce objectionable results inthe paper. It may be made from any chemically prepared or cooked woodfiber, including chemical pulp of southern pine or southern gumwood, orfrom other suitable cellulose material,

but preferably is made from the same.

bleached sulphate fiber as is used in the pulp furnish. Propertransformation of wood fiber to the colloidal state may be offected bybeating in a standard beater, for a period of from twelve to fifteenhours; but it may be more quickly efi'cted, in about three hours, bytreatment continuously and in rotation by a beater and a J ordan engineconnected in series.

As more particularly illustrating the nature and characteristics of ourinvention, we give as follows a description of the No.1 quality..southern pine sulphate used in making a certain run of paper ac cordingto the invention, withouthowever implying any limitation of ourprotection to the exact steps, ingredients, or proportions so.described. The furnish was coinposed of:

Per cent.

pulp, bleached;

Ground black gumwood; '70. Colloidal I cellulose To the above totalfiber furnish there was added,;for the usual purpose of sizing, 1 70 ofrosin size and 1% of alum. The sulphate pulp was-made from NorthCarolina pine and was bleached by standard chlorine bleaching equipment.The ground pulp was made from black gumwood obta ned from the swamps ofthe Pearl River. M ssissippi, by the operation of a standard wood pulpgrinder with a stone commonly used-for the production er pulp fornewsprint use. buried "with a four-cut straight burr and operated with agrinding pressure of thirty pounds per square inch on a fourteen inchcylinder. The colloidal cellulose was made from chemical wood pulp byhydration in a standard beater and Jordan, connected in a series andoperated in repeated rotation on the stock. v The furnish thusconstituted was made into paper on a standard Fourdrinier paper machine,which was run in the usual way for making newsprint paper.

Paper -made as thus particularly described has been used with entiresatisfaction in printing the regular editions of daily newspapers onhigh speedrotary perfecting newspaper presses of types which makeexacting demands on the paper web.

While'the specific proportions of the in gredients illustrativelydescribed above are preferred at present to others, neverthelessconsiderable variations in such proportions may be made, and equivalentingredients may be substituted, within the protection herein claimed.For instance, the southern pine sulphate fiber and gumwood fibers may beused in other proportions, although always with a substantialpreponderance of the ground fiber; and other flocculent agglutinantshaving the functions hereinbefore ascribed to the agglutinant may beused in place of colloidal cellulose; while colloidal celluloseotherwise made in any suitable manner may be used.

Our invention has thus made possible the manufacture of commercialnewsprint paper from southern pine and southern gumwood and has therebyrendered available to the industry great quantities of wood heretoforeunavailable for this use.

While we have made this result possible by modifying the fiber furnish,consisting The stone was of medium gritchiefly of mechanical gumwoodpulp, by

adding thereto an ingredient or agent, namely colloidal cellulose, whichhas the capacity of making an otherwise unworkable fiber mixturefeltable into strong pa per in a paper machinel,nevertheless theprotection which we claim is not limited to the use of an added feltingagent or to paper containing such felting agent. we are the first tohave produced a workable furnish composed wholly of southern pinechemical pulp and gumwood mechanical pulp, and are the first to makemerchantable newsprint paper of these ingredients, we claim protectiongenerically for means and methods of making such workable furnish, andfor our products, commensurate with the novelty of our invention;

, The woods designated by the words southern pine as used in thisspecification include the following: short leaf yellow (Pin'use-chinata'), long leaf-yellow, and Georgia long leaf (Pi'lmspalustris),Cuban pine ,(Pz'nus hezfcrophylla), loblolly pine (Pin-us swam orPz'mes" taeda), and, in

Since general, all pines found in the southern United States andcharacterized by'a resin content substantially greater than that of thenorthern conifers. The term guinwood as here used, includes black gum(Ng ssa, syloatica), cotton gum (Ng ssa aguatz'ca), sweet or red gum(Liguidambar stg mciflua), and the like.

What we claim and desire to secure by Letters Patent is:

1. The method of making newsprint paper froma fiber furnish consistingof southern gumwood ground pulp and southern pine sulphate pulp, whichconsists in modifying said furnish by incorporating colloidal cellulosetherewith, in substantially the proportions specified, and then formingsaid modified furnish into a paper web.

2. The method of making newsprint paper which embraces supplying to thepaper machine a fiber furnish having as one component a chemical pulp,as another and major component southern gumwood pulp of such characterthat it would not so felt with the chemical component that the furnishcould be carried over the paper machine, and a flocculent agglutinant tomodify the felting capacity of the furnish to enable it to be carriedover the paper machine.

3. The method of making newsprint paper which embraces supplying to thepaper making machine a furnish consisting of southern pine sulphatepulp, southern gumwood ground pulp, and material to effect a feltingaction between the two components, and forming said furnish into a paperweb on the machine.

4. The method of making newsprint paper from southern pine and groundgumwood 80% ground gumwood and 80% to 20% southern pine sulphate pulp toprovide a sufliciently felting furnish to pass over the paper makingmachine, and forming the furnish into a paper web.

5. The method of making newsprint paper from southern pine and gumwoodWhich comprises preparing a fiber furnish of southern pine sulphate pulpand mechanically disintegrated gumwood, with treatment of the gumwood tomake its fibers sufficiently feltable to enable the furnish to pass overthe paper making machine, and forming said furnish into a paper We 6.The method of making a paper furnish from southern pine sulphate pulpandgumwood ground pulp which consists in incorporating with said gumwoodpulp chemical wood fiber colloidal cellulose in substantially theproportions specified.

7. The method of transforming an unworkable paper furnish consistingchiefly of mechanical gumwood pulp of such character that it would notbe carried over the paper machine which comprises incorporatingcolloidal cellulose in said furnish in substantially the proportionsspecified and thereby causing the fibers to become feltable into asuitable paper web.

8. The method of making a newsprint paper furnish from southern pinesulphate pulp and gumwood ground pu p which consists in combining saidingredients in the ratio of approximately 70% to 80% of the groundgumwood and the balance of south ern pine sulphate pulp.

9. Newsprint paper composed of southern pine sulphate pulp, mechanicalgumwood pulp, andcolloidal cellulose.

10. Newsprint paper composed of a mixture of southern pine sulphatepulp, mechanical gumwood pulp, and a flocculent agglutinant.

11. A paper furnish for the manufacture of newsprint paper consisting ofsouthern pine sulphate pulp, southern gumwood ground pulp, and chemicalwood fiber colloidal cellulose in substantially the proporlionsspecified.

12. A paper furnish for the manufacture of newsprint paper consisting ofsouthern pine sulphate pulp and gumwood ground pulp, and a felting agentin suflicient measure to make said furnish sufiiciently feltable toenable the furnish to pass over the paper making machine.

In testimony whereof we have affixed our signatures.

ARTHUR D. LITTLE. CARROLL E. CARPENTER.

